Vehicle supplemental heating system

ABSTRACT

Disclosed herein is a supplemental heating system including a liquid heat generator having a hydrodynamic chamber for selectively heating a fluid. The hydrodynamic chamber having an inlet port for delivering the fluid to the hydrodynamic chamber, and a discharge port for removing heated fluid from the hydrodynamic chamber. The inlet port is fluidly connected to a first check valve and the discharge port is fluidly connected to a second check valve. The first check valve adapted to receive an input from the second check valve. The first check valve operable to close the fluid path between the first check valve and the inlet port in response to an input received from the second check valve.

RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 60/843,083 filed on Sep. 8, 2006, which is incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates in general to heat generators, and moreparticularly, to a supplemental liquid heating system for providingsupplemental heat to a passenger compartment of an automotive vehicle.

BACKGROUND

Conventional automotive vehicles typically include a heating system forsupplying warm air to a passenger compartment of the vehicle. Theheating system includes a control system that allows a vehicle operatorto regulate the quantity and/or temperature of air delivered to thepassenger compartment so as to achieve a desirable air temperaturewithin the passenger compartment. Cooling fluid from the vehicle'sengine cooling system is commonly used as a source of heat for heatingthe air delivered to the passenger compartment.

The heating system typically includes a heat exchanger fluidly connectedto the vehicle's engine cooling system. Warm cooling fluid from theengine cooling system passes through the heat exchanger where and givesup heat to a cool air supply flowing through the heating system. Theheat energy transferred from the warm cooling fluid to the cool airsupply causes the temperature of the air to rise. The heated air isdischarged into the passenger compartment to warm the interior of thevehicle to a desired air temperature.

The vehicle's engine cooling system provides a convenient source of heatfor heating the vehicle's passenger compartment. One disadvantage ofusing the engine cooling fluid as a heat source, however, is that thereis typically a significant delay between when the vehicle's engine isfirst started and when the heating system begins supplying air at apreferred temperature. This is particularly true when the vehicle isoperated in very cold ambient conditions or has sat idle for a period oftime. The delay is due to the cooling fluid being at substantially thesame temperature as the air flowing through the heating system and intothe passenger compartment when the engine is first started. As theengine continues to operate, a portion of the heat generated as abyproduct of combusting a mixture of fuel and air in the enginecylinders is transferred to the cooling fluid, causing the temperatureof the cooling fluid to rise. Since, the temperature of the air beingdischarged from the heating system is a function of the temperature ofthe cooling fluid passing through the heat exchanger, the heating systemwill produce proportionally less heat while the engine cooling fluid iswarming up than when the cooling fluid is at a preferred operatingtemperature. Thus, there may be an extended period of time between whenthe vehicle's engine is first started and when the heating system beginsproducing air at an acceptable temperature level. The time it takes forthis to occur will vary depending on various factors, including theinitial temperature of the cooling fluid and the initial temperature ofthe air being heated. It is preferable that the temperature of thecooling fluid reach its preferred operating temperature as quickly aspossible.

Another potential limitation of using the engine cooling fluid as a heatsource for the vehicle's heating system is that under certain operatingconditions the engine may not be rejecting enough heat to the coolingfluid to enable the air stream from the vehicle's heating system toachieve a desired temperature. This may occur, for example, whenoperating a vehicle with a very efficient engine under a low loadcondition or in conditions where the outside ambient temperature isunusually cold. Both of these conditions reduce the amount of heat thatneeds to be transferred from the engine to the cooling fluid to maintaina desired engine operating temperature. This results in less heat energyavailable for heating the air flowing through the vehicle's heatingsystem.

Accordingly it is desirable to develop a supplemental heating systemcapable of intermittently providing additional heating of an engine'scooling fluid so as to improve the heating efficiency of the vehicles'passenger compartment heating system.

SUMMARY

A supplemental heating system is provided including a liquid heatgenerator having a hydrodynamic chamber for selectively heating a fluid.The hydrodynamic chamber having an inlet port for delivering the fluidto the hydrodynamic chamber, and a discharge port for removing heatedfluid from the hydrodynamic chamber. The inlet port is fluidly connectedto a first check valve and the discharge port is fluidly connected to asecond check valve. The first check valve adapted to receive an inputfrom the second check valve. The first check valve operable to close thefluid path between the first check valve and the inlet port in responseto an input received from the second check valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and accompanying drawings, wherein:

FIG. 1 is a schematic depiction of a conventional engine cooling systemand passenger compartment heating system;

FIG. 2 is schematic depiction of the vehicle supplemental heating systemof the present invention integrated with the engine cooling system andheating shown in FIG. 1;

FIG. 3 is a schematic depiction of a supplemental heating systemincorporating a spool valve for controlling distribution of coolingfluid within the system;

FIG. 4 is a is a front perspective view of the supplemental heatingsystem employing the spool valve;

FIG. 5 is top elevational view of a fluid distribution module of thesupplemental heating system;

FIG. 6 is rear elevational view of the fluid distribution module of thesupplemental heating system;

FIG. 7 is a top elevational view of the supplemental heating system withthe fluid distribution module removed;

FIG. 8 is a cross-sectional view of the fluid distribution module takenalong section 8-8 of FIG. 7, showing a spool valve located in a bypassmode position;

FIG. 9 is a partial cross-sectional view of the fluid distributionmodule of FIG. 8 showing details of the spool valve;

FIG. 10 is a cross-sectional view of the fluid distribution module takenalong section 8-8 of FIG. 7, showing a spool valve located in adedicated mode position;

FIG. 11 is a partial cross-sectional view of the fluid distributionmodule of FIG. 10 showing details of the spool valve;

FIG. 12 is a cross-sectional view of the fluid distribution module takenalong section 8-8 of FIG. 7, showing a spool valve located in adedicated mode with modulation;

FIG. 13 is a partial cross-sectional view of the fluid distributionmodule of FIG. 12 showing details of the spool valve;

FIG. 14 is a side elevational view of the spool valve deployed in thesupplemental heating system, shown fully retracted;

FIG. 15 is a cross-sectional view of the spool valve of FIG. 14, takenalong section 15-15;

FIG. 16 is a side elevational view of the spool of the fluiddistribution module, shown fully expanded;

FIG. 17 is a cross-sectional view of the spool of FIG. 16, taken alongsection 17-17;

FIG. 18 is a cross-sectional view of the fluid distribution module takenalong section 18-18 of FIG. 5;

FIG. 19 is a cross-sectional view of the fluid distribution module takenalong section 19-19 of FIG. 5;

FIG. 20 is a schematic depiction of a supplemental heating systemincorporating a dual check valve fluid distribution module forcontrolling distribution of cooling fluid within the system;

FIG. 21 is a front perspective view of the supplemental heating systemdeploying the dual check valve fluid distribution module;

FIG. 22 is a rear perspective view of the supplemental heating systemdeploying the dual check valve fluid distribution module;

FIG. 23 is an exploded rear perspective view of the dual check valvefluid distribution module;

FIG. 24 is a partially exploded front view of the dual check valve fluiddistribution module;

FIG. 25 is a top elevational view of the supplemental heating systemwith the dual check valve fluid distribution module removed;

FIG. 26 is a top elevation view of the dual check valve fluiddistribution module shown detached from the supplemental heating system;

FIG. 27 is cross-section view of the dual check valve fluid distributionmodule taken along section 27-27;

FIG. 28 is cross-section view of the dual check valve fluid distributionmodule taken along section 28-28, showing a driven check valve locatedin a dedicated mode position;

FIG. 29 is cross-section view of the dual check valve fluid distributionmodule taken along section 28-28, showing the driven check valve locatedin the bypass mode position;

FIG. 30 is cross-section view of the dual check valve fluid distributionmodule taken along section 30-30, showing a drive check valve located ina dedicated mode position;

FIG. 31 is cross-section view of the dual check valve fluid distributionmodule taken along section 30-30, showing the drive check valve locatedin the bypass mode position;

FIG. 32 is a cross-sectional view of pressure relief valve deployed withthe supplemental heating system;

FIG. 33 is a cross-section view of the pressure relief valve of FIG. 31,further incorporating a metering orifice;

FIG. 34 is a schematic depiction of the supplemental heating systememploying the spool valve, the supplemental heating system having aninlet fluidly connected to a vehicle water pump; and

FIG. 35 is a schematic depiction of the supplemental heating systememploying the dual check valve fluid distribution module, thesupplemental heating system having an inlet fluidly connected to thevehicle water pump.

DESCRIPTION OF PREFERRED EMBODIMENTS

The following description of the preferred embodiments is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Referring to FIG. 1, a conventional vehicle cooling system 40 forregulating the operating temperature of an engine 42 may include a waterpump 44, which circulates a cooling fluid 46 through engine 42. Coolingfluid 46 absorbs heat produced by engine 42 as a byproduct of combustinga mixture of fuel and air in cylinders 48 of engine 42 to produce usablemechanical work for propelling the vehicle. Engine 42 includes anaccessory drive 50 for providing power to drive various vehicleaccessories, such as a generator, air conditioning compressor, and waterpump 44. Accessory drive 50 is connected to a crankshaft 52 of engine42. Water pump 44 is connected to accessory drive 50 by means of drivebelt 54, which engages a sheave 56 of water pump 44. Heat from engine 42is transferred to cooling fluid 46 as it circulates through passagesformed in an engine block 58. Cooling fluid 46 is discharged from engine42 through an engine discharge port 60, and depending on the temperatureof the cooling fluid exiting the engine, is either directed to waterpump 44 through a water pump supply passage 62, or to a radiator 64through a radiator supply passage 66.

A thermostat 65 controls distribution of cooling fluid 46 between waterpump supply passage 62 and radiator supply passage 66. Thermostat 65 mayinclude a thermally activated valve 68 that automatically adjusts athru-flow area of the thermostat in response to a change in thetemperature of cooling fluid 46 exiting engine 42 through dischargepassage 60. Thermostat 65 can be calibrated to begin opening at adesired cooling fluid temperature. Thermostat 65 may be closed atcooling fluid temperatures below the calibrated temperature to preventcooling fluid 46 from traveling to radiator 64 through supply passage66. At a temperature at or slightly above the calibrated temperature,thermostat 65 will begin to open and allow a portion of cooling fluid 46to pass through radiator supply passage 66 to radiator 64. Thermostat 65may be fully open at cooling fluid temperatures significantly higherthan the calibrated temperature, which will maximize the fluid flow rateto radiator 64 for a particular vehicle operating condition.

Cooling fluid 46 flowing through radiator supply passage 66 entersradiator 64 through an inlet port 70. Cooling fluid 46 passes throughradiator 64, where a portion of its heat can be transferred to a streamof ambient air 72 flowing crosswise through the radiator. Cooling fluid46 exits radiator 64 through an outlet port 74 at a lower temperaturethan when it entered. Upon exiting radiator 64, cooling fluid 46 travelsthrough a radiator discharge passage 76 to water pump 44.

Engine cooling system 40 may include an expansion tank 78 fluidlyconnected to water pump 44 through expansion tank supply passage 77.Expansion tank 78 provides a reservoir for capturing cooling fluid 46discharged from cooling system 40, which may occur for example, when thecooling fluid expands due to heating following an engine cold start.Conversely, a portion of cooling fluid 46 may be withdrawn fromexpansion tank 78 and returned to cooling system 40 through expansiontank supply passage 77 when, for example, the temperature of the coolingfluid decreases after turning off engine 42.

Conventional automotive vehicles typically include a heating system 80that provides a supply of warm air 82 for heating a passengercompartment 84 of the vehicle. Heating system 80 includes a cabin heatexchanger 86, which is fluidly connected to cooling system 40 through aheater inlet passage 88 and heater exit passage 90. Heater inlet passage88 can be fluidly connected to cooling system 40 at thermostat 65, oranother suitable location. A portion of cooling fluid 46 exiting engine42 at engine discharge port 60 passes through heater inlet passage 88 tocabin heat exchanger 86. Cooling fluid 46 may reject a portion of itsheat to airstream 82 flowing through cabin heat exchanger 86. Airstream82 may consist of air drawn from outside the vehicle, from passengercompartment 84, or a combination thereof. Airstream 82 exits cabin heatexchanger 86 at a higher temperature than when it entered. Airstream 82can be discharged into passenger compartment 84 to warm the interior ofthe vehicle. Airstream 82 can also be directed to flow over an interiorglass surface of the vehicle to remove frost or condensation that mayhave formed on the glass surface. Heating system 80 may also includevarious control devices for regulating the temperature and flow rate ofairstream 82 delivered to passenger compartment 84.

Referring also to FIG. 2, a supplemental heating system (SHS) 92 may befluidly connected between cooling system 40 and heating system 80.Supplemental heating system 92 controls distribution of cooling fluid 46between cooling system 40 and heating system 80, as well as providingadditional heat, if necessary, to cooling fluid 46 supplied to cabinheat exchanger 86.

Supplemental heating system 92 can be fluidly connected to coolingsystem 40 through heater inlet passage 88 and heater exit passage 90.Heater inlet and exit passages 88 and 90 are fluidly connected tosupplemental heating system 92 at a port 94 and 96, respectively.Cooling fluid 46 can be transferred from cooling system 40 tosupplemental heating system 92 through heater inlet passage 88 andreturned through heater exit passage 90.

Supplemental heating system 92 may be fluidly connected to cabin heatexchanger 86 through a cabin heat exchanger inlet passage 88 a connectedto a port 98 of the supplemental heating system, and a cabin heatexchanger discharge passage 90 a connected to a port 100. Cooling fluid46 circulating within supplemental heating system 92 can exit the systemat port 98 and travel through heater inlet passage 88 a to cabin heatexchanger 86, where a portion of the heat from cooling fluid 46 can betransferred to airstream 82. Upon exiting cabin heat exchanger 86,cooling fluid 46 can be directed back to supplemental heating system 92through heater discharge exit passage 90 a.

Referring also to FIG. 3, supplemental heating system 92 includes aliquid heat generator (LHG) 102 for heating cooling fluid 46 supplied tocabin heat exchanger 86. An example of one such liquid heat generator isdisclosed in U.S. Pat. No. 5,683,031, entitled Liquid Heat Generator,which issued to Sanger on Nov. 4, 1997. The U.S. Pat. No. 5,683,031patent is incorporated herein by reference. Supplemental heating system92 may also include a control valve 104 for controlling distribution ofcooling fluid 46 within supplemental heating system 92, and a controller106 for regulating operation of liquid heat generator 102 and controlvalve 104.

Liquid heat generator 102 includes a stator 108 and a coaxially alignedrotor 110 positioned adjacent stator 108. Stator 108 is fixedly attachedto a housing 112 of the supplemental heating system. Rotor 110 can bemounted on a drive shaft 114 for concurrent rotation therewith about anaxis 116. Stator 108 and rotor 110 define annular cavities 118 and 120,respectively, which together define a hydrodynamic chamber 122. Heatingof cooling fluid 46 occurs within hydrodynamic chamber 122.

Hydrodynamic chamber 122 can be fluidly connected to cooling system 40through heater inlet passage 88. Cooling fluid 46 from cooling system 40travels through a coolant supply passage 124 connected to heater inletpassage 88 at port 94. Fluidly attached to supply passage 124 at fluidjunction 126 is a hydrodynamic chamber supply passage 128. Cooling fluid46 passing through hydrodynamic chamber supply passage 128 is dischargedto a hollow cavity 132 formed in the back of rotor 110. One or morerotor passages 134 fluidly connect cavity 132 to hydrodynamic chamber122. Rotor passage 134 extends through a blade 136 of rotor 110, and hasone end fluidly connected to cavity 132 and an opposite end tohydrodynamic chamber 122.

Cooling fluid 46 present in hydrodynamic chamber 122 travels along agenerally toroidal path within the chamber, absorbing heat as the fluidtravels between annular cavities 118 and 120 of stator 108 and rotor110, respectively. Heated cooling fluid 46 exits hydrodynamic chamber122 through one or more discharge orifices 138 located along a back wall139 of stator 80 near its outer circumference. Orifice 138 can befluidly connected to a circumferential annulus 140 formed in housing112. Annulus 140 can be fluidly connected to a liquid heat generatordischarge passage 142. Cooling fluid 46 exiting hydrodynamic chamber 122through orifice 138 can travel through discharge passage 142 todischarge port 98.

Cooling fluid 46 exits supplemental heating system 92 at port 98 andtravels along cabin heat exchanger inlet passage 88 a to cabin heatexchanger 86. Heat from cooling fluid 46 can be transferred to airstream82 as the fluid passes through the heat exchanger. The warm airstreammay be directed to passenger compartment 84 to warm the interior of thevehicle.

After passing through cabin heat exchanger 86, cooling fluid 46 exitsthe heat exchanger and returns to supplemental heating system 92 throughcabin heat exchanger discharge passage 90 a, which is fluidly connectedto supplemental heating system 92 at port 100. Cooling fluid 46 passesthrough a cabin heater return passage 144 having one end fluidlyconnected to port 100 and an opposite end fluidly connected to controlvalve 104. A cooling system return passage 146 fluidly connects controlvalve 104 to cooling system 40 at port 96, and a liquid heat generatorrecirculating passage 148 fluidly connects control valve 104 to liquidbeat generator 102. Control valve 104 can either direct all or a portionof cooling fluid 46 to recirculating passage 148 or to cooling systemreturn passage 146, depending on the particular heating requirements ofheating system 80. Having control valve 104 direct substantially all ofthe cooling fluid received from cabin heat exchanger 86 to liquid heatgenerator 102 through recirculating passage 148 results in heatingsystem 80 and cooling system 40 operating substantially independent ofone another.

Cooling fluid 46 passing through recirculating passage 148 can bedischarged to an annular plenum 150 in housing 112. A second plenum 151fluidly connects plenum 150 to hydrodynamic chamber 122. Cooling fluid46 preferably enters hydrodynamic chamber 122 at an inner circumferenceof the chamber.

Cooling fluid 46 passing through cooling system return passage 146 exitssupplemental heating system 92 at port 96. Cooling fluid 46 can travelto water pump 44 through heater exit passage 90, which has one endfluidly connected to the supplemental heating system 92 at port 96, andan opposite end fluidly connected to water pump 44.

Supplemental heating system 92 may include a bypass passage 152 havingone end fluidly connected to fluid supply passage 124 and hydrodynamicchamber supply passage 128 at fluid junction 126, and an opposite endfluidly connected to liquid heat generator discharge passage 142 atfluid junction 154. Cooling fluid 46 passing through bypass passage 152bypasses hydrodynamic chamber 122, and is instead sent directly to cabinheat exchanger 86 without any additional heat being added to the fluid.A check valve 156, or another similar device, may be provided in bypasspassage 152 to prevent fluid from flowing backwards through bypasspassage 152, from fluid junction 154 to fluid junction 126, whenoperating liquid heat generator 102. Cooling fluid 46 entering liquidheat generator discharge passage 142 from bypass passage 152 travels toport 98, where the fluid exits supplemental heating system 92.

Control valve 104 controls distribution of cooling fluid 46 betweencooling system return passage 146, fluidly connected to heater exitpassage 90 at port 96, and liquid beat generator recirculating passage148, fluidly connected to liquid heat generator 102. Control valve 104operates to selectively distribute cooling fluid 46 between coolingsystem return passage 146 and liquid heat generator recirculatingpassage 148, based on certain preselected parameters. This may includedirecting all of the cooling fluid received from heat exchanger returnpassage 144 to either cooling system return passage 146 or liquid heatgenerator recirculating passage 148, or apportioning the cooling fluidbetween the two passages. Control valve 104 is preferably infinitelyadjustable.

Power for rotateably driving rotor 110 can be supplied by engine 42. Anend 158 of drive shaft 114 extends from housing 112 of supplementalheating system 92. Fixedly attached to end 158 is a drive means 160,which may include a sheave 162 engageable with engine accessory drivebelt 27. Accessory drive belt 27 engages accessory drive 50 attached tocrankshaft 52 of engine 42. Drive belt 27 may also deliver the powerrequired to operate water pump 44, as well as other engine accessories,such as an alternator and air conditioning compressor. Accessory drivebelt 27 transfers torque generated by engine 42 to drive shaft 1141,which is connected to rotor 110. It is also contemplated that driveshaft 114 may be alternatively driven by another suitable means, such asan electric motor.

Drive means 160 can include a clutch 164, which may, for example andwithout limitation, be an electromagnetic clutch. Clutch 164 can beselectively engaged in response to the particular heating requirementsof heating system 80. Clutch 164 can be operated to disengage rotor 110from engine 42 when no additional heating of cooling fluid 46 isrequired, which may be desirable to minimize the power being drawn fromengine 42 for improving engine efficiency and to help maximize theamount of power available for other uses, such as propelling thevehicle.

Hydrodynamic chamber 122 of heat generator 102 may be vented toatmosphere through a vent passage 166. One end of vent passage 166 canbe fluidly connected to an annular plenum 168 in housing 112, and anopposite end fluidly connected to a vent exit port 170 located along anexterior surface of housing 112. An expansion tank vent passage 172 canfluidly connect vent passage 166 to expansion tank 78. It is preferablethat cooling fluid 46 only partially fill expansion tank 78 to providean air space 174 within the expansion tank. Expansion tank vent passage172 is preferably attached to expansion tank 78 at a location adjacentair space 174 to prevent vent passage 172 from being in direct fluidcommunication with cooling fluid 46 present in expansion tank 72. Stator108 may include one or more blade vent passages 176 fluidly connectingplenum 168 to hydrodynamic chamber 122. Blade vent passage 176 passthrough a center of a stator blade 177 extending from back wall 139 ofstator 108.

Controller 106 can be adapted to regulate operation of liquid heatgenerator 102 and control valve 104. Controller 106 may be, by way ofexample and without limitation, a programmable microprocessor.Controller 106 is operably connected to control valve 104 by means of aconnector 178. Controller 106 can send a control signal to control valve104 for controlling operation of control valve 104 and regulatingdistribution of the cooling fluid between cooling system return passage146 and liquid heat generator recirculating passage 148.

Controller 106 may be adapted to control operation of clutch 164, whichis operably connected to control unit 106 by means of a connector 179.Controller 106 can send a control signal to clutch 164 instructing theclutch to either engage or disengage depending on the heatingrequirements of heating system 80. Engaging clutch 164 enables torquefrom engine 42 to be applied to shaft 114 through drive belt 27, therebycausing rotor 110 to rotate about axis 116 and heat cooling fluid 46present in hydrodynamic chamber 122. Disengaging clutch 164 decouplesshaft 114 and rotor 110 from engine 42. With clutch 164 disengaged,liquid heat generator 102 does not produce any heat since rotor 110 isnot being rotateably driven by belt 27.

Controller 106 may be adapted to monitor various operating parameters ofsupplemental heating system 92, including by way of example and withoutlimitation, the rotational speed of rotor 110, a temperature of coolingfluid 46 entering liquid heat generator 102 through liquid heatgenerator recirculating passage 148, and the pressure level of coolingfluid 46 exiting liquid heat generator 102 through liquid heat generatordischarge passage 142. The rotational speed of rotor 110 may bemonitored by means of a speed pickup 180, which may include any ofvariety of known speed pickup devices, for example and withoutlimitation, an electromagnetic pickup. An electromagnetic pickup mayinclude a magnetized material suitably attached to a back wall 182 ofrotor 110. A sensor 184 adapted to detect the magnetic field of themagnetized material attached to rotor 10 can be suitably attached tohousing 112. A connector 186 operably connects speed pickup 180 tocontroller 106. It is also contemplated that electromagnetic pickup 180may be suitably mounted to various other locations, by way of examplewithout limitation, drive means 106.

The temperature of cooling fluid 46 entering liquid heat generator 102through liquid heat generator recirculating passage 148 may be monitoredby means of a temperature probe 188, which may include any of a varietyof known temperature sensing devices, for example and withoutlimitation, a thermocouple and a resistance temperature detector.Temperature probe 188 can be suitably located within liquid heatgenerator recirculating passage 148, or another suitable location, whichenables temperature probe 188 to detect a temperature of cooling fluid46 passing through the passage. A conventional connector 190 operablyconnects temperature probe 188 to controller 106. Temperature probe 188can be adapted to produce a signal indicative of the temperature of thecooling fluid present in the passage.

The pressure of cooling fluid 46 exiting liquid heat generator 102through liquid heat generator discharge passage 142 can be monitored bymeans of a pressure probe 192, which may include any of a variety ofknown pressure sensing devices. Pressure probe 192 is preferably locatedwithin liquid heat generator discharge passage 142 near dischargeorifice 138, or another suitable location, which enables pressure probe192 to detect the pressure of cooling fluid 46 exiting hydrodynamicchamber 122. Pressure probe 192 can be adapted to generate a signalindicative of the pressure of the cooling fluid passing throughdischarge passage 142. A connector 194 operably connects pressure probe192 to controller 106.

Referring also to FIGS. 4-7, the various components of supplementalheating system 92 may be conveniently packaged as a unitized assemblyfor installation in the vehicle. Attached to housing 112, using one ormore fasteners 196, is a fluid distribution module 198. Fasteners 196are engageable with a threaded aperture 199 in housing 112.Alternatively, it is contemplated that fluid distribution module 198 maybe positioned remotely from housing 112, which may require additionalfluid passages to fluidly connect the module to liquid heat generator102.

Fluid distribution module 198 includes a manifold 200 for distributingcooling fluid 46 between supplemental heating system 92, engine coolingsystem 40, and cabin heat exchanger 86. Attached to manifold 200 iscontrol valve 104, which operates to control distribution of coolingfluid received through cabin heat exchanger return passage 144, betweencooling system return passage 146 and liquid heat generatorrecirculating passage 148. Fluid distribution module 198 may include oneor more external connectors for fluidly connecting supplemental heatingsystem 92 to engine cooling system 40 and heating system 80.Supplemental heating system 92 can be retrofitted to an existingvehicle, or incorporated as original equipment on a newly manufacturedvehicle, by fluidly connecting heater inlet passage 88 and heater exitpassage 90 to ports 94 and 96, respectively, of supplemental heatingsystem 92. Similarly, cabin heat exchanger 86 can be fluidly connectedto supplemental heating system 92 by connecting cabin heat exchangerinlet passage 88 a and discharge passage 90 a to ports 98 and 100,respectively.

Referring also to FIGS. 8 through 13, manifold 200 includes a generallycylindrically shaped hollow cavity 202 extending partially through themanifold. Cavity 202 has an open end 204 accessible from outsidemanifold 200, and a partially closed end 205 opposite open end 204. Aninner diameter of cavity 202 is substantially constant overapproximately the first half the cavity's length starting at open end204. Approximately midway along the length of cavity 202, the innerdiameter steps down to a second smaller diameter, creating a shoulder206 intermediate the two ends of cavity 202.

Fluidly connected to cavity 202 adjacent partially closed end 205, iscabin heat exchanger return passage 144. Cabin heat exchanger returnpassage 144 can be fluidly connected to port 100. Port 100 may have anelongated cylindrical shape adapted to receive an end of cabin heatexchanger discharge passage 90 a. Also fluidly connected to partiallyclosed end 205 of cavity 202 is cooling system return passage 146.Cooling system return passage 146 terminates at port 96. Port 96 mayhave an elongated cylindrical shape adapted to receive an end of heaterdischarge passage 90 a. Liquid heat generator recirculating passage 148fluidly connects to a generally middle region of cavity 202.

Fluid distribution module 198 may include a generally cup shaped controlvalve mounting sleeve 210 having an open first end 212 and a partiallyclosed second end 214 disposed within cavity 202 of manifold 200. Anouter surface of mounting sleeve 210 can be stepped to correspond to thestepped profile of cavity 202. An O-ring 218 can be disposed in anannular cavity 220 formed between the inner surface of cavity 202 andthe outer surface of mounting sleeve 210.

A radial flange 220 extends outward from end 212 of mounting sleeve 210.Flange 220 abuts an outer surface 221 of manifold 200 when mountingsleeve 210 is fully inserted in cavity 202. An aperture 222 formed inend 214 of mounting sleeve 210 fluidly connects an inner region 224 ofmounting sleeve 210 to cooling system return passage 146. One or moreorifices 226 extend through a sidewall 228 of mounting sleeve 210adjacent end 214. Orifices 226 fluidly connect heat exchanger returnpassage 144 to the inner region 224 of mounting sleeve 210. A secondorifice 229, for fluidly connecting inner region 224 of mounting sleeve210 to liquid heat generator recirculating passage 148, traversessidewall 228 of mounting sleeve 210 intermediate the first and secondends. A recessed slot 230 extends circumferentially along an inner bore234 of mounting sleeve sidewall 228, and is generally aligned axially tocoincide with orifice 229.

Referring also to FIGS. 14 through 16, control valve 104 includes acylindrically shaped spool 232 slideably disposed within bore 234 of amounting sleeve 210. Spool 232 includes a hollow cylindrically shapedbypass piston 236. Extending radially outward from one end of bypasspiston 236 is an outer flange 238. An outer circumference 240 of theflange slideably engages bore 234 of mounting sleeve 210. One or moreorifices 242 extending through a sidewall 244 of bypass piston 236 arelocated adjacent flange 238. The orifices enable cooling fluid to passbetween the inner and outer regions of bypass piston 236.

Extending radially inward from an inner surface 246 of sidewall 244 isan inner flange 248. Flange 248 is displaced inward of an end 250 ofbypass piston 236 opposite flange 238. A shaft seal 252 may beinternally disposed within end 250 of bypass piston 236, and abuts innerflange 248.

Spool 232 may also include a cylindrically shaped modulating piston 254having an end section 256 partially disposed within bypass piston 236.Extending radially outward from an end 258 of modulating piston 254,opposite outer flange 238 of bypass piston 236, is a flange 260. Flange260 may include a circumferential notch 262 extending along an outercircumference 264 of the flange. A seal material 266 may be disposedwithin notch 262. Seal 266 can slideably engage bore 234 of mountingsleeve 210. End section 256 of modulating piston 254, opposite flange260, can be necked down to allow the modulating piston to be partiallydisposed within bypass piston 236. The necked down region forms ashoulder 268, against which end 250 of bypass piston 236 can abut whenend section 256 of modulating piston 254 is fully inserted into bypasspiston 236. An inner circumference of seal 252 can slideably engage anouter surface of necked down region 256 of modulation piston 254.

An end 269 of modulating piston 254, opposite flange 260, engages a bore270 of a ring shaped retaining block 272. An outer circumference 274 ofretaining block 272 slideably engages inner surface 246 of bypass piston236. Retaining block 272 can be affixed to an end of modulating piston254 by means of a retaining ring 278. Retaining ring 278 can engage acircumferential notch 280 formed in end 269 of modulating piston 254.

Bypass piston 236 and modulating piston 254 are free to move axiallyrelative to one another. A biasing member 282 can be disposed within anannular space 284 formed between bypass piston 236 and modulating piston254. Biasing member 282 urges bypass piston 236 and modulating pistontoward one another, such that end 250 of bypass piston 236 contactsshoulder 268 of modulating piston 254. Biasing member 282 may be a coilspring, or another similar device, including but not limited to, anelastic cylinder or a leaf spring. One end 286 of the biasing memberengages retaining block 272 and an opposite end 288 engages inner flange248 of bypass piston 236.

Spool 232 is in a fully compressed state when end 250 of bypass piston236 contacts shoulder 268 of modulating piston 254. Spool 232 can beexpanded by applying outwardly opposing forces to flange 238 of bypasspiston 236 and flange 260 of modulating piston 245 sufficient toovercome the spring rate of biasing member 282. The opposing forces tendto cause end 250 of bypass piston 236 to move away from shoulder 268 ofmodulating piston 254, thereby causing spool 232 to expand.

With spool 232 fully compressed, such that end 250 of bypass piston 236contacts shoulder 268 of modulating piston 254, retaining block 272 isaxially aligned with orifices 242 in bypass piston 236, which willsubstantially prevent cooling fluid from flowing through orifices 242.Spool 232 can be sufficiently expanded (i.e., increasing the distancebetween bypass flange 238 and modulating flange 260) to allow an end 290of retaining block 272 to clear orifices 242, which will enable coolingfluid pass through the orifices.

Axial movement of spool 232 within bore 234 of mounting sleeve 210 canbe controlled by an actuator 292, which may include, for example andwithout limitation, a solenoid or piezo-electric actuator. Actuator 292may include a movable drive link 294 extending from and end 296 of theactuator. An end of drive link 294 can engage a receiving passage 298formed in end 258 of modulating piston 254. Drive link 294 can beattached to modulating piston 254 by means of a roll pin 300, whichengages a pair of radially extending apertures 302 in modulating piston254, and a corresponding aperture 303 extending through drive link 294.Alternatively, it is also contemplated that other suitable connectingdevices, including but not limited to screws, rivets and bolts, may alsobe used to secure spool 232 to drive link 294. End 296 of actuator 292may include a boss 302 that is engageable with bore 234 of mountingsleeve 210, which may assist in obtaining proper alignment of theactuator relative to mounting sleeve 210. Actuator 292 and mountingsleeve 210 may be attached to manifold 200 using one or more bolts 304that simultaneously extend through apertures in a flange 306 of actuator292 and flange 220 of mounting sleeve 210, and which threadably engage acorresponding aperture in manifold 200. Alternatively, it is alsocontemplated that another suitable attaching means, for example andwithout limitation, screws and rivets, may also be used to attachmounting sleeve 210 and actuator 292 to manifold 200.

Actuator 292 is operable to selectively position spool 232 at a desiredlocation within bore 234 of mounting sleeve 210. Actuator 292 may beoperably connected to controller 106, which may be adapted to controloperation of the actuator.

Supplemental heating system 92 may be operated in various modesdepending on the heating requirement of heating system 80. For exampleand without limitation, a bypass mode, wherein cooling fluid 46 receivedfrom cabin heat exchanger 86 is returned to engine cooling system 40,and a dedicated mode, wherein cooling fluid from cabin heat exchanger 86is recirculated back to liquid heat generator 102.

When operating in the bypass mode, actuator 292 can be activated toslide spool 232 toward the actuator and away from aperture 222 in endwall 214 of mounting sleeve 210, as shown in FIGS. 8 and 9. This opensthe fluid path between fluid passages 144 and 146, thereby enablingcooling fluid 46 to be directed back to cooling system 40, while at thesame time closing the fluid path between fluid passages 144 and 148.Liquid heat generator 92 may or may not be operating, depending on theparticular heating requirements of the vehicle. For example, ifsupplemental heating system 92 is primarily used to provide additionalheat to the vehicle cabin, liquid heat generator 92 will generally bedeactivated when spool 232 is located in the bypass position. Liquidheat generator 92 can be deactivated by disengaging clutch 164, whichdecouples rotor 110 from engine accessory drive 50. Fluid enteringsupplemental heating system 92 at port 94 will pass through supplypassage 124 to fluid junction 126. A majority of the cooling fluidarriving at fluid junction 126 will proceed to pass through bypasspassage 152 and check valve 156. The cooling fluid will continue to flowto fluid junction 154, where it can be discharged to liquid heatgenerator discharge passage 142. Cooling fluid 42 exits supplementalheating system 92 at port 98 and can be directed to cabin heat exchanger86 through cabin heat exchanger inlet passage 88 a. After passingthrough heat exchanger 86, the cooling fluid is directed back tosupplemental heating system 92 through cabin heat exchanger dischargepassage 90 a. Cooling fluid entering supplement heating system 92 atport 100 can travel through cabin heat exchanger return passage 144 tocontrol valve 104. Since spool 232 is positioned in the bypass position,fluid from cabin heat exchanger return passage 144 will pass throughorifices 226 in mounting sleeve 210, and into interior cavity region 224of mounting sleeve 210. From there, cooling fluid 46 may flow throughaperture 222 in end wall 214 of mounting sleeve 210 to cooling systemreturn passage 146.

With liquid heat generator 102 deactivated, a relatively small amount ofcooling fluid 46 passing through supply passage 124 may neverthelessflow through hydrodynamic chamber supply passage 128 to hydrodynamicchamber 122. The vast majority of fluid, however, will flow throughbypass passage 152. The small amount of cooling fluid enteringhydrodynamic chamber 122 will be discharged to expansion tank 78 throughvent passage 166 and expansion tank vent passage 172.

It may be desirable to operate liquid heat generator 102 with spool 232positioned in the bypass position, for example, following an engine coldstart to accelerate warming of the engine. With liquid heat generator102 activated, cooling fluid arriving at fluid junction 126 will proceedto flow through hydrodynamic chamber supply passage 128 to hydrodynamicchamber 122, rather than through bypass passage 152. Heated coolingfluid 46 can flow from hydrodynamic chamber 122 to liquid heat generatordischarge passage 142. From that point, the cooling fluid follows thesame path as when the liquid heat generator is not operating, passingthrough cabin heat exchanger 86 and onto control valve 104, which is setto direct the cooling fluid back to engine cooling system 40 throughcooling system return passage 146.

When operating supplemental heating system 92 in the dedicated mode,actuator 292 can be activated to slide spool 232 away from the actuatorand toward aperture 222 in end wall 214 of mounting sleeve 210, suchthat flange 238 of bypass piston 236 engages end wall 214 of themounting sleeve, as shown in FIGS. 10 and 11. This opens the fluid pathbetween fluid passages 144 and 148, thereby enabling cooling fluid 46 tobe directed back to liquid heat generator 102, while at the same timeclosing the fluid path between fluid passages 144 and 146. Cooling fluidis prevented from entering cooling system return passage 146 whenoperating the supplemental heating system in the dedicated mode.

The dedicated mode can be initiated by engaging clutch 164 to activateliquid heat generator 102, causing rotor 110 to rotate about axis 116.Control valve 104 is preferably positioned in the bypass position whenclutch 164 is first engaged, and is thereafter moved to the dedicatedposition. Cooling fluid 46 entering supplemental heating system 92through port 94 flows along coolant supply passage 124 to fluid junction126. Rather than entering bypass passage 152, as is the case whenoperating in the bypass mode, the cooling fluid flows throughhydrodynamic chamber supply passage 128 to hydrodynamic chamber 122. Thecooling fluid follows the previously described path through liquid heatgenerator 102, exiting hydrodynamic chamber 122 at discharge port 138.Heated cooling fluid 46 travels through liquid heat generator dischargepassage 142 to port 98, where the fluid exits supplemental heatingsystem 92. From port 98, cooling fluid 46 travels through cabin heatexchanger inlet passage 88 a to cabin heat exchanger 86, where a portionof the fluid heat can be transferred to airstream 82. Upon exiting cabinheat exchanger 86, the cooling fluid is directed back to supplementalheating system 92 through cabin heat exchanger discharge passage 90 a,where it reenters supplemental heating system 92 at port 100. Coolingfluid 46 passes through heat exchanger return passage 144 to controlvalve 104. With control valve 104 positioned in the dedicated position,cooling fluid is blocked from flowing through aperture 222 to coolingsystem return passage 146, and instead is directed back to liquid heatgenerator 102 through liquid heat generator recirculating passage 148.Cooling fluid from return passage 144 passes through orifices 226traversing sidewall 228 of the mounting sleeve, and flows around theouter circumference of bypass piston 236. Cooling fluid 46 passesthrough orifices 229 traversing the sidewall of the mounting sleeve, andinto liquid heat generator recirculating passage 148, which directs thecooling fluid back to liquid heat generator 102.

To avoid over pressurizing hydrodynamic chamber 122 when operating inthe dedicated mode, spool 232 is operable to enable a portion of coolingfluid received from heat exchanger return passage 144 to be directed tocooling system return passage 146, which transfers the cooling fluidback to engine cooling system 40, as shown in FIGS. 12 and 13. Directinga portion of the cooling fluid to passage 146 may cause a correspondingdrop in pressure within hydrodynamic chamber 122. The pressure levelwithin hydrodynamic chamber 122 can be approximated by monitoring thepressure level within liquid heat generator discharge passage 142 bymeans of pressure gage 192. As the pressure level within hydrodynamicchamber 122 increases, so does the pressure level within annular cavity308 between spool 232 and mounting sleeve 210. Increasing the pressurewithin annular cavity 308 beyond a predetermined level will causemodulating piston 254 to move away from bypass piston 236, and at leastpartially unblock orifices 242 in bypass piston 236, thereby enablingcooling fluid to flow through the orifices from heat exchanger returnpassage 144 to cooling system return passage 146. Bleeding off of smallportion of cooling fluid in this way may cause a corresponding drop inpressure within hydrodynamic chamber 122. As the pressure level withinhydrodynamic chamber 122 decreases, modulating piston 254 and bypasspiston 236 move toward one another, causing retaining sleeve 272 toblock the flow of coolant from return passage 144 to cooling systemreturn passage 146.

Referring to FIGS. 20 through 22, supplemental heating system 92 mayinclude a dual check valve fluid distribution module 310 incorporating apair of cooperative check valves for controlling distribution of coolingfluid 46 within supplemental heating system 92. Fluid distributionmodule 310 performs a similar function as control valve 104, and may beused in place of control valve 104. In addition to check valve 156, asecond check valve 312 can be substituted in place of control valve 104.Check valve 312 has an inlet fluidly connected to heat exchanger returnpassage 144, a first outlet to cooling system return passage 146, and asecond outlet to recirculating passage 148. Check valves 156 and 312 maybe cooperatively interconnected, such that movement of check valve 156(the drive check valve) causes a corresponding movement of check valve312 (the driven check valve). The two check valves may be interconnectedby any variety of means, including but not limited to mechanical,electrical, hydraulic, and pneumatic means. The cooperativeinterconnection between drive check valve 156 and driven check valve 312is represented by dashed line 313 in FIG. 20.

Drive check valve 156 operates to prevent cooling fluid from flowingfrom liquid heat exchanger discharge passage 142 to bypass passage 152when liquid heat generator 102 is operating. Driven check valve 312operates in response to input from drive check valve 156, to directcooling fluid received from return passage 144 to either cooling systemreturn passage 146, or recirculating passage 148, depending on whetherthe supplemental heating system is operating in the bypass or dedicatedmode.

Referring also to FIGS. 23 through 31, fluid distribution module 310 mayalso included is a pressure regulating valve 314 selectively operable tofluidly connect recirculating passage 148 to cooling system returnpassage 146. An inlet bleed passage 316 fluidly connects recirculatingpassage 148 to an inlet of pressure regulating valve 314. A dischargebleed passage 318 fluidly connects an outlet of pressure regulatingvalve 314 to cooling system return passage 146.

Fluid distribution module 310 may include a manifold 320 that can besecurely fastened to liquid heat generator housing 112 by means of oneor more fasteners 322 that pass through an aperture 323 in the manifoldbody and threadably engage a corresponding aperture 324 in housing 112.Alternatively, it is also contemplated that fluid distribution module310 may be located remotely from housing 112, which may requireadditional fluid lines to fluidly connect the distribution module toliquid heat generator 102.

Manifold 320 may include an upper surface 328, a lower surface 330, afront surface 332, and a rear surface 334. Extending inward from lowersurface 330 is a drive check valve cavity 336 for receiving drive checkvalve 156. Drive check valve cavity 336 can be fluidly connected toliquid heat generator discharge passage 142 extending through liquidheat exchanger housing 112. Also extending inward from lower surface 330is a driven check valve cavity 338 for receiving driven check valve 312.Driven check valve cavity 338 can be fluidly connected to recirculatingpassage 148 passing through liquid heat generator housing 112.

Extending from front surface 332 of manifold 320 is cabin heat exchangerreturn passage 144, which terminates at port 100, and liquid heatgenerator discharge passage 142, which is a continuation of dischargepassage 142 passing though liquid heat generator housing 112. Liquidheat generator discharge passage terminates at port 98. Heat Exchangerdischarge passage 144 is fluidly connected to driven check valve cavity338, and return passage 142 is fluidly connected to driven check valvecavity 336.

Extending from rear surface 334 of manifold 320 is cooling system returnpassage 146, which terminates at port 96, and coolant supply passage124, which terminates at port 94. Cooling system return passage 146 isfluidly connected to driven check valve cavity 338, and coolant supplypassage 124 is fluidly connected to drive check valve cavity 336.Coolant supply passage 124 may also be fluidly connected to hydrodynamicchamber supply passage 128, which extends through liquid heat generatorhousing 112. Cooling system return passage 146 may be fluidly connectedto bleed discharge passage 318, which may consist of a slot formed in anupper surface 363 of liquid heat generator housing 112.

Attached to manifold 320 is pressure regulating valve 314. Pressureregulating valve 314 may include an actuator 340 that engages anaperture 342 extending vertically through manifold 320. Pressureregulating valve 314 includes a valve spindle 344 that can beselectively extended and retracted within a housing 346 of the actuator.A disk shaped pintal 348 can be attached to an end of valve spindle 344.

Pressure regulating valve 314 may also include a cup shaped bleed valveseat 350 that also engages aperture 342 in manifold 320. Valve seat 350may have an upstanding cylindrical sidewall 352 and a bottom wall 354.An end 356 of sidewall 352 can engage an end 358 of actuator 340.Located near a center of bottom wall is a bleed inlet orifice 360, whichcorresponds to inlet bleed passage 316 (see FIG. 20). Orifice 360 is influid communication with recirculating passage 148 that extends intoliquid heat generator housing 112. Actuator 340 can control the flow ofcooling fluid through orifice 360 by extending valve spindle 344 toengage pintal 348 with a circumferential edge of orifice 360, therebysealing off the fluid path through the orifice. Conversely, coolingfluid can be permitted to flow through orifice 360 by retracting valvespindle 344 to disengage pintal 348 from orifice 360. Located adjacentinlet orifice 360 is a bleed discharge orifice 362. Orifice 362 isfluidly connected to bleed discharge passage 318.

Drive check valve 156 can be positioned within drive check valve cavity336. Driven check valve 312 can similarly be positioned with drivencheck valve cavity 338. The two check valves can be fixedly attached toa common shaft 364, such that movement of drive valve 156 produces acorresponding movement of driven check valve 312. Drive shaft 364 issupported in a pair of apertures 366 extending through sidewall 352 ofvalve seat 350. A washer 368 can engage a recessed notch 370 formed inbottom surface 330 of manifold 320. Washer 368 provides a valve seat fordrive check valve 156 when the drive check valve is operated in thebypass mode.

Drive check valve 156 and driven check valve 312 are simultaneouslyrotateable about an axis of shaft 364, between a bypass position and adedicated position. When rotated into the dedicated position, drivecheck valve 156 is positioned adjacent an end 370 of bypass passage 152,as shown in FIG. 30, and driven check valve 312 is positioned adjacentand end engages an end 372 of cooling system return passage 146, asshown in FIG. 28. With drive check valve 156 and driven check valve 312rotated into the bypass position, as shown in FIGS. 31 and 29,respectively, drive check valve is seated against washer 368, and drivencheck valve 312 is positioned horizontally to at least partially blockthe entrance to recirculating passage 148.

As described previously, heating system 92 may be operated in the bypassmode, wherein cooling fluid 46 from cabin exchanger 86 is returned toengine cooling system 40, or in the dedicated mode, wherein coolingfluid 46 from cabin heat exchanger 86 is re-circulated back to liquidheat generator 102. To operate in the dedicated mode, liquid heatgenerator 102 can be activated by engaging clutch 164. Activating liquidheat generator 102 causes cooling fluid to flow from hydrodynamicchamber 122 through liquid heat generator discharge passage 142 to cabinheat exchanger 86. Cooling fluid 46 present in liquid heat generatordischarge passage 142 will be at a higher pressure than that the coolingfluid present in bypass passage 152, which will cause drive check valve156 to be rotated into the dedicated position adjacent end 370 of bypasspassage 152. This will prevent cooling fluid from flowing between liquidheat generator discharge passage 142 and bypass passage 152. Becausedrive check valve 156 and driven check valve 312 are operablyinterconnected, activating liquid heat generator 102 will also causedriven check valve 312 to rotate to the dedicated mode position adjacentend 372 of cooling system return passage 146, thereby directing coolingfluid 46 received from heat exchanger 86 back to hydrodynamic chamber122.

Controller 106 can monitor the pressure within recirculating passage 148when operating supplemental heating system in the dedicated mode. If thepressure level within recirculating passage 148 exceeds somepredetermined level, controller 106 can send a control signal toactuator 340, instructing the actuator to commence bleeding coolingfluid from recirculating passage 148 to cooling system return passage146, which will cause a corresponding reduction in the pressure withinhydrodynamic chamber 122. Once the pressure within recirculating passage148 falls below a maximum desired pressure level, pressure regulatingvalve 314 will be instructed by control unit 106 to stop bleeding fluidfrom recirculating passage 148 to cooling system return passage 146.

To operate in the bypass mode, liquid heat generator 102 is deactivatedby disengaging clutch 164. With liquid heat generator 102 deactivated,the fluid in bypass passage 152 will be at a higher pressure than thefluid in liquid heat generator discharge passage 142. This will causedrive check valve 156 to open the flow path between bypass passage 152and liquid heat generator bypass passage 142, which will allow coolingfluid from engine cooling system 40 to bypass hydrodynamic chamber 122and flow directly to heat exchanger 86. Driven check valve 312, beingoperably linked to drive check valve 156, will seal off the flow pathbetween cabin heat exchanger return passage 144 and recirculatingpassage 148, and open the flow path between cabin heat exchanger returnpassage 144 and cooling system return passage 146. This will cause thecooling fluid discharged from heat exchanger 86 to bypass hydrodynamicchamber 122, and instead be directed back to engine cooling system 40.

Referring to FIGS. 3, 32 and 33, supplemental heating system 92 mayinclude a pressure relief valve 376 positioned between back wall 182 ofrotor 110 and housing 112, which is operable for limiting a maximuminternal operating pressure within hydrodynamic chamber 122. Pressurerelief valve 376 includes a flexible disk shaped diaphragm 380 having anouter circumferential edge 382 attached to back wall 182 of rotor 110.Diaphragm 380 may include an aperture 384 located at a center of thediaphragm 380 for receiving a seal 386. Seal 386 includes a tubularshaped seal ring 388. Attached to an outer surface 390 of seal ring 388is a grommet 392 for attaching seal ring 388 to a circumferential edgeof aperture 392. A lateral end 394 of seal ring 388 slideably engages aring shaped seal seat 396 fixedly attached to housing 112. A biasingmember 398, such as spring or other elastic material, may be providedfor urging seal ring 388 into contact with seal seat 396. Biasing member398 is trapped axially between rotor 110 and seal grommet 392 in acompressed state, thereby urging seal ring 388 away from rotor 110 andinto contact with ring seat 396.

Pressure relief valve 376 operates to help control a maximum pressurewithin hydrodynamic chamber 122 by allowing a small quantity of fluid tobe discharged from a cavity 400 between housing 112 and back wall 182 ofrotor 110, to hydrodynamic chamber supply passage 128 when the internalpressure exceeds some predetermined level.

Cooling fluid from engine cooling system 40 can be supplied tohydrodynamic chamber 122 through hydrodynamic chamber supply passage128. The cooling fluid passes through an orifice 402 in seal seat 396and through an internal passage 404 in seal ring 388. The cooling fluidtravels radially outward through cavity 132 formed between back wall 182of rotor 110 and diaphragm 380. The cooling fluid enters one or morepassages 134 in blades 136 of rotor 110, and is discharged along theinterface between stator 108 and rotor 110.

The fluid pressure within hydrodynamic chamber 122 is dependant on,among other things, the mass quantity of fluid present within thechamber. Hydrodynamic chamber 122 is in fluid communication with cavity400 between housing 112 and the back of rotor 110, and the pressurewithin cavity 400 can reasonably approximate the pressure withinhydrodynamic chamber 122. As the pressure increases within hydrodynamicchamber 122, so does the pressure within cavity 400. An increase inpressure within cavity 400 will generally increase the pressure dropacross diaphragm 380. When the pressure within cavity 400 reaches alevel at which the pressure force applied along the cavity 400 side ofdiaphragm 380 exceeds the sum of the pressure force being exerted alongthe opposite cavity 132 side of the diaphragm, plus the biasing force ofbiasing member 398, seal ring 388 will become disengaged from ring seat396, thereby allowing a quantity of cooling fluid to flow from cavity400 to hydrodynamic chamber supply passage 128. This will result in adecrease in the quantity of fluid present within hydrodynamic chamber122, which will produce a corresponding decrease in pressure within thehydrodynamic chamber. As the pressure within hydrodynamic chamber 122continues to decrease, seal ring 388 will move toward seal seat 396until the pressure within hydrodynamic chamber 122 is below a desiredlevel, at which point seal ring 386 will seat against ring seat 396 andprevent any further flow of fluid between cavity 400 and supply passage128. The pressure level at which seal ring 388 begins to be displacedfrom ring seat 396 can be calibrated by adjusting the spring rate ofbiasing member 398.

With reference to FIG. 33, to aid in the operation of the pressurerelief valve 376, seal ring 388 may include a calibrated orifice plate408, which operates to restrict the flow area through seal ring 388 andincrease the differential pressure across diaphragm 380. The forcetending to move seal ring 388 away from ring seat 396 would thus be thesum of the pressure force applied to the cavity 400 side of diaphragm380 plus the pressure force applied to the supply passage 128 side oforifice plate 408.

Under certain operating conditions, it may be possible to improve theperformance of pressure relief valve 376 by fluidly connectinghydrodynamic chamber supply passage 128 to an inlet of water pump 44rather than thermostat 65. This can be accomplished for a supplementalheating system utilizing fluid distribution module 198 incorporating thespool valve, by altering the fluid connections shown in FIG. 3 tocorrespond with those shown in FIG. 34. Instead of fluidly connectinghydrodynamic chamber supply passage 128 to fluid junction 126,hydrodynamic chamber supply passage 128 can be fluidly connected tocooling system return passage 146. A similar modification can be donefor a supplemental heating system incorporating dual check valve fluiddistribution module 310, as FIG. 35.

The description of the invention is merely exemplary in nature, andthus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A heating apparatus connectable to an enginecooling system of a vehicle, the cooling system including a coolingfluid circulating within the cooling system and a heat exchanger fortransferring heat from the cooling fluid to an airstream for heating apassenger compartment of the vehicle, the heating apparatus comprising:a liquid heat generator having a hydrodynamic chamber operable forselectively heating the cooling fluid present within the hydrodynamicchamber when the heating apparatus is connected to the cooling system,the hydrodynamic chamber having an inlet port and a discharge port; afirst valve including an inlet port fluidly connectible to an exit portof the heat exchanger, a first discharge port fluidly connected to theinlet port of the hydrodynamic chamber and second discharge port fluidlyconnectable to the engine cooling system, the first valve operable forselectively adjusting a fluid path between the first valve and the inletport of the hydrodynamic chamber; and a second valve having a firstinlet port fluidly connected to the discharge port of the hydrodynamicchamber, a second inlet port fluidly connectable to the engine coolingsystem and a discharge port fluidly connectable to an inlet port of theheat exchanger, the second valve operably connected to the first valve,wherein the first valve adjusts the fluid path between the first valveand the inlet port of the hydrodynamic chamber in response to an inputreceived from the second valve, and wherein the first valve isadjustable to fluidly connect the inlet port of the first valve to thesecond discharge port of the first valve in response to adjusting thesecond valve to fluidly connect the second inlet port of the secondvalve to the outlet port of the second valve.
 2. The heating apparatusof claim 1 , wherein the first valve is adjustable to fluidly connectthe inlet port of the first valve to the first discharge port of thefirst valve in response to adjusting the second valve to fluidly connectthe first inlet port of the second valve to the outlet port of thesecond valve.
 3. The heating apparatus of claim 1 , wherein the secondvalve fluidly connects the first inlet port of the second valve to theoutlet port of the second valve when the hydrodynamic chamber isoperating.
 4. The heating apparatus of claim 1 , wherein the secondvalve fluidly connects the second inlet port of the second valve to theoutlet port of the second valve when the hydrodynamic chamber is notoperating.
 5. The heating apparatus of claim 1 , wherein the first valvefluidly connects the inlet port of the first valve to the first outletport of the first valve when the hydrodynamic chamber is operating. 6.The heating apparatus of claim 1 , wherein the first valve fluidlyconnects the inlet port of the first valve to the second outlet port ofthe first valve when the hydrodynamic chamber is not operating.
 7. Aheating apparatus connectable to an engine cooling system of a vehicle,the cooling system including a cooling fluid circulating within thecooling system and a heat exchanger for transferring heat from thecooling fluid to an airstream for heating a passenger compartment of thevehicle, the heating apparatus comprising: a liquid heat generatorhaving a hydrodynamic chamber operable for selectively heating thecooling fluid present within the hydrodynamic chamber when the heatingapparatus is connected to the cooling system, the hydrodynamic chamberhaving an inlet port and a discharge port; a first valve having a firstdischarge port fluidly connected to the inlet port of the hydrodynamicchamber, the first valve operable for selectively adjusting a fluid pathbetween the first valve and the inlet port of the hydrodynamic chamber,the first valve including an inlet port fluidly connectible to an exit-port of the heat exchanger and a second discharge port fluidlyconnectable to the engine cooling system; a second valve having a firstinlet port fluidly connected to the discharge port of the hydrodynamicchamber, the second valve operably connected to the first valve, whereinthe first valve adjusts the fluid path between the first valve and theinlet port of the hydrodynamic chamber in response to an input receivedfrom the second valve, the second valve including a second inlet portfluidly connectable to the engine cooling system and a discharge portfluidly connectable to an inlet port of the heat exchanger; and a thirdvalve having an inlet passage fluidly connected to the inlet port of thefirst valve, and an outlet passage fluidly connected to the secondoutlet port of the first valve.
 8. The heating apparatus of claim 7,wherein the third valve is operable to selectively connect the inletport of the first valve fluidly to the second outlet port of the firstvalve when the hydrodynamic chamber is operating.
 9. The heatingapparatus of claim 1, wherein the first and second valves operate inunison.
 10. The heating apparatus of claim 1, wherein operation of oneof the first valve and the second valve is controlled by the remainingvalve.
 11. The heating apparatus of claim 10, wherein the first valvecomprises a first valve flap and the second valve comprises a secondvalve flap, the heating apparatus further comprising an actuating linkoperably connecting the first valve flap to the second valve flap. 12.The heating apparatus of claim 11, wherein the second valve flap ismoveable between a first position, in which the second valve flapsubstantially blocks a fluid path between the first inlet port of thesecond valve and the of the second valve, and a second position, inwhich the second valve flap substantially blocks a fluid path betweenthe second inlet port of the second valve and the discharge port of thesecond valve.
 13. The heating apparatus of claim 12, wherein a flow pathbetween the inlet port of the first valve and the second discharge portof the first valve is substantially blocked when the second valve flapis positioned in its second position.
 14. The heating apparatus of claim11, wherein the actuating link comprises a shaft rotatable about alongitudinal axis of the shaft, wherein the first and second valve flapsare fixedly attached to the shaft for concurrent rotation therewith. 15.The heating apparatus of claim 11, wherein the first valve flap isselectively moveable between a first position, in which the first valveflap substantially blocks a fluid path between the inlet port of thefirst valve and the first discharge port of the first valve, and asecond position, in which a fluid path between the inlet port of thefirst valve and the first discharge port of the first valve issubstantially unimpeded by the first valve flap.
 16. The heatingapparatus of claim 10, wherein the inlet port of the first valve isfluidly connected to the first discharge passage of the first valve inresponse to adjusting the second valve to fluidly connect the firstinlet port of the second valve to the discharge port of the secondvalve.
 17. The heating apparatus of claim 16, wherein the inlet port thefirst valve is fluidly connected to the second discharge port of thefirst valve in response to adjusting the second valve to fluidly connectthe second inlet port of the second valve to the discharge port of thesecond valve.
 18. The heating apparatus of claim 10, further comprisingof third valve having a valve seat, a valve spindle selectivelyengageable with the valve seat, and an actuator connected to the valvespindle, the actuator operable for selectively disengaging the valvespindle from the valve seat.
 19. A heating system for providing heat toa passenger compartment of a vehicle, the heating system comprising: anengine cooling system including a cooling fluid; a heat exchangeroperable for transferring heat from the cooling fluid to an airstreamdeliverable to the passenger compartment; a liquid heat generator havinga hydrodynamic chamber operable for selectively heating the coolingfluid present within the hydrodynamic chamber when the heating apparatusis connected to the cooling system, the hydrodynamic chamber having aninlet port and a discharge port; a first valve having an inlet portfluidly connected to a discharge port of the heat exchanger, a firstdischarge port fluidly connected to the inlet port of the hydrodynamicchamber and a second discharge port fluidly connected to the enginecooling system, the first valve operable for selectively adjusting afluid path between the first valve and the inlet port of thehydrodynamic chamber and blocking a fluid flow path between the heatexchanger and the engine cooling system; and a second valve having adischarge port fluidly connected to an inlet port of the heat exchangerand a first inlet port fluidly connected to the discharge port of thehydrodynamic chamber, the second valve operably connected to the firstvalve and operable for selectively blocking a fluid flow path betweenthe hydrodynamic chamber and the heat exchanger, wherein the first valveadjusts the fluid path between the first valve and the inlet port of thehydrodynamic chamber in response to an input received from the secondvalve.
 20. The heating apparatus of claim 19, further comprising anactuating link operably connecting the first valve to the second valve,wherein movement of one of the two valves produces concurrent movementof the remaining valve.
 21. The heating apparatus of claim 20, whereinthe second valve further comprises a second inlet port fluidly connectedto the engine cooling system.
 22. The heating apparatus of claim 21,wherein the first valve is adjustable to open a fluid path between thedischarge port of the heat exchanger and the engine cooling system inresponse to the second valve substantially blocking a fluid path betweenthe discharge port of the hydrodynamic chamber and the inlet port of theheat exchanger.
 23. The heating of claim 21, wherein the first valve isadjustable to substantially block a fluid path between the dischargeport of the heat exchanger and the engine cooling system in response tothe second valve substantially blocking a fluid path between the enginecooling system and the inlet port of the heat exchanger.
 24. The heatingof claim 19, further comprising: a bleed valve having an inlet passagefluidly connected to the discharge port of the heat exchanger and anoutlet passage fluidly connected to the engine cooling system, whereinthe bleed valve is operable for selectively establishing a fluid pathbetween the discharge port of the heat exchanger and the engine coolingsystem.
 25. The heating apparatus of claim 24, wherein the bleed valveis operable to selectively establish a fluid path between the dischargeport of the heat exchanger and the engine cooling system when the firstvalve is adjusted to substantially block the fluid path between thedischarge port of the heat exchanger and the engine cooling system.